Seroprevalence and Microbiological Monitoring in Eggs for Salmonella enterica Serovar Enteritidis and Salmonella enterica Serovar Typhimurium in Ornamental Chicken Flocks in Italy

Few data are available about the prevalence of Salmonella enterica serovar Enteritidis (S.E.) and Salmonella enterica serovar Typhimurium (S. T.) in ornamental poultry in Italy. The aim of this study was to investigate the seroprevalence for S.E. and S.T. using serological tests and the prevalence of Salmonella spp. in eggs by culture methods. For this purpose, 240 serum samples and 216 eggs were sampled from asymptomatic and unvaccinated ornamental hens reared in 24 farms, located in 8 different Italian regions. As screening test, a Tube Serum Agglutination test (TSA) was performed on 231 out of 240 serum samples. Four out of 24 farms (16.67%) were serologically positive for Salmonella spp. for a total of 10 samples. These positive samples were confirmed using an ELISA test and the results show that 5/231 (2.16%) and 7/231 (3.03%) serum samples were positive for S.E. and S.T. respectively, and 2/231 (0.87%) for both serotypes. Among all farms, 2/24 (8.33%) were positive for S.E. and 4/24 (16.67%) for S.T. The analysis of eggs using culture methods gave negative results for both yolk and shell pools (0/48, 0.0%). The seroconversion associated with exposure to S.E./S.T. in ornamental poultry, poses a potential public health problem. This study confirms that S.E. and S.T. are widespread in studied backyard poultry farms as asymptomatic form, and animals as potential reservoirs of Salmonella. It is necessary to inform farmers that a regular and periodic control of animals, eggs or meat, is very important to prevention of Salmonella foodborne infections and their spread. (C) 2020 PVJ. All rights reserved